Missions in space face the problem of spacecrafts being exposed to a wide range of radiation. One type of radiation involves charged particles and ions, which can have a deteriorating effect on the outside surface of spacecrafts and can damage external equipment such as solar cells and sensors.
The source of this radiation can vary (e.g., solar flares and cosmic rays) as can the velocities and charges of the particles and ions. Fortunately, the trajectory of these types of charged particles and ions can be altered in a number of ways.
For example, an electrostatic field could change the path of charged particles. However, generating large electrostatic fields around a spacecraft can create its own set of problems. This includes the possible effect of such a field on electronic equipment. Further, there is no low-cost means at present to deploy a power source to create such fields for a spacecraft.
Another method to protect against this dangerous radiation would be the use of heavy shielding. However, this method tends to be cost prohibitive due to the expense of placing such heavy shielding into space.
A preferable alternative is the use of magnetic fields. Moving charged particles interact with the magnetic field and the result can be a deflection of the particle. In such a case, it would be desirable to generate a powerful field to entirely protect a spacecraft from all directions and from all types of incoming particles. Unfortunately, generating such a field around a spacecraft requires a great deal of energy especially for larger crafts. Usually such energy sources are not available for spacecraft at present that are sufficiently light and cost effective to be used for such an application.
What is needed is a magnetic shield that can protect specific parts of a spacecraft that are more likely to be subjected to charged particles or ion radiation, while not requiring that the entire craft be protected by the shield.